MIR 3.6.1

The Recognised Investment Exchange must make arrangements for the price, volume and time of transactions executed in Financial Instruments to be made available to the public and the Regulator as close to real‐time as technically possible assuming a reasonable level of efficiency and of expenditure on systems on the part of the Recognised Investment Exchange, provided that:
(a) information relating to a portfolio trade shall be made available with respect to each constituent transaction as close to real time as possible, having regard to the need to allocate prices to particular Financial Instruments; and
(b) post‐trade information referring to transactions taking place on a Recognised Investment Exchange but outside its normal trading hours shall be made public before the opening of the next trading day of the Recognised Investment Exchange.